ONLINE SUPPLEMENT
Predictors of residual sleepiness in adequately treated obstructive
sleep apnoea patients
I.Koutsourelakis, E.Perraki, P.Dimitrokalli, N.T.Economou, E. Vagiakis, C.Roussos,
S. Zakynthinos
AFFILIATIONS
Center of Sleep Disorders
Medical School of Athens University,
Department of Critical Care and Pulmonary Services,
Evangelismos Hospital
CORRESPONDENCE
Ioannis Koutsourelakis, MD
Medical School of Athens University,
Center of Sleep Disorders,
Evangelismos Hospital, 45-47 Ipsilandou Str,
GR 106 75, Athens, Greece
Tel: 0030 210 72 01 843, Fax: 0030 210 72 01 843
E-mail: ykoutsourelakis@yahoo.gr
The present work was funded by the Thorax Foundation.
Table 1S. Demographic, clinical and polysomnographic features of the OSAS patients
with excessive daytime sleepiness (ESS score > 10) determined at baseline
assessment. Patients who exhibited after CPAP treatment (mean daily use ≥ 5 hours
during follow-up period) normal ESS score (< 11) were defined as CPAP responders,
whereas those who exhibited after CPAP treatment abnormal ESS score (> 10) thus
demonstrating residual excessive daytime sleepiness were defined as CPAP nonresponders.
CPAP responders
CPAP non-repsonders
n=89
n=36
Age (years)
50.7±12.5
61.4±10.8**
Body mass index (kg∙m-2)
33.9±7.1
32.8±7.3
86.5
69.4#
Respiratory disturbance index
58.9±34.2
40.5±26.6*
ESS score
14.0±3.0
16.1±3.4*
5.6
30.6**
0
50.0**
Hypothyroidism (%)
5.6
11.1
Alcohol use (%)
16.9
11.1
Heart disease (%)
39.3
63.9#
COPD (%)
7.9
25.0*
Stroke (%)
12.4
11.1
Smoke (%)
40.4
47.2
REM/TST (%)
11.8±7.8
10.5±7.4
S1/TST (%)
5.5±6.3
5.6±5.3
S2/TST (%)
80.0±14.7
75.8±18.6
SWS/TST (%)
2.5±8.8
7.2±16.7
Average oxygen saturation (%)
89.6±5.9
90.5±5.0#
Lowest oxygen saturation (%)
71.6±10.7
74.0±11.4
Male (%)
Diabetes (%)
Depression (%)
Continuous data are presented as mean ± SD. #: p<0.05 versus CPAP responders; *:
p<0.01 versus CPAP responders;**: p<0.001 versus CPAP responders. ESS: Epworth
sleepiness scale; COPD: chronic obstructive pulmonary disease; TST: total sleep
time; REM: rapid eye movement sleep; SWS: slow wave sleep.
Table 2S. Demographic, clinical and polysomnographic features of the OSAS patients
with excessive daytime sleepiness (ESS score > 10) determined at baseline
assessment. Patients who exhibited after CPAP treatment (mean daily use ≥ 6 hours
during follow-up period) normal ESS score (< 11) were defined as CPAP responders,
whereas those who exhibited after CPAP treatment abnormal ESS score (> 10) thus
demonstrating residual excessive daytime sleepiness were defined as CPAP nonresponders.
CPAP responders
CPAP non-repsonders
n=69
n=25
Age (years)
48.5±11.4
60.7±11.4**
Body mass index (kg∙m-2)
34.2±7.1
32.4±8.2
88.4
68.0#
61.2 ±34.7
33.2±24.0**
14.0±3.2
15.3±3.1
7.2
28.0*
0
60.0**
Hypothyroidism (%)
7.2
12.0
Alcohol use (%)
17.4
12.0
Heart disease (%)
40.6
64.0#
COPD (%)
4.3
20.0*
Stroke (%)
5.8
8.0
Smoke (%)
43.5
52.0
REM/TST (%)
11.5±7.8
11.8±7.3
S1/TST (%)
6.0±6.9
5.5±5.8
S2/TST (%)
79.3±15.9
73.3±16.7
SWS/TST (%)
3.2±9.9
7.8±15.8
Average oxygen saturation (%)
89.3±6.3
91.9±3.6
Lowest oxygen saturation (%)
71.5±10.9
77.7±9.3#
Male (%)
Respiratory disturbance index
ESS score
Diabetes (%)
Depression (%)
Continuous data are presented as mean ± SD. #: p<0.05 versus CPAP responders; *:
p<0.01 versus CPAP responders;**: p<0.001 versus CPAP responders. ESS: Epworth
sleepiness scale; COPD: chronic obstructive pulmonary disease; TST: total sleep
time; REM: rapid eye movement sleep; SWS: slow wave sleep.
Table 3S. Univariate and multivariate predictors of residual excessive daytime
sleepiness after CPAP therapy.
UNIVARIATE ANALYSIS MULTIVARIATE ANALYSIS
Cutoff 4 hours per day
OR (95% CI)
p
OR (95% CI)
p
10.66 (4.31-26.41)
<0.001
6.87 (2.50-18.91)
<0.001
Heart disease (0 = no, 1 = yes)
3.07 (1.74-5.41)
<0.001
2.94 (1.41-6.15)
0.004
Epworth sleepiness scale score
1.28 (1.15-1.42)
<0.001
1.31 (1.15-1.49)
<0.001
Respiratory disturbance index
0.98 (0.97-0.99)
0.001
0.97 (0.96-0.98)
<0.001
OR (95% CI)
p
OR (95% CI)
p
Diabetes (0 = no, 1 = yes)
7.39 (2.34-23.28)
0.001
5.83 (1.59-21.33)
0.008
Heart disease (0 = no, 1 = yes)
2.73 (1.22-6.10)
0.014
1.77 (0.70-4.50)
0.229
Epworth sleepiness scale score
1.21 (1.07-1.36)
0.002
1.30 (1.12-1.52)
0.001
Respiratory disturbance index
0.98 (0.97-0.99)
0.006
0.97 (0.96-0.99)
0.002
OR (95% CI)
p
OR (95% CI)
p
Diabetes (0 = no, 1 = yes)
4.98 (1.41-17.57)
0.013
4.22 (0.98-18.13)
0.053
Heart disease (0 = no, 1 = yes)
2.60 (1.01-6.71)
0.048
1.38 (0.46-4.13)
0.561
Epworth sleepiness scale score
1.13 (0.98-1.30)
0.082
1.22 (1.02-1.45)
0.032
Respiratory disturbance index
0.97 (0.95-0.99)
0.001
0.97 (0.95-0.99)
0.001
Diabetes (0 = no, 1 = yes)
Cutoff 5 hours per day
Cutoff 6 hours per day
Cutoff values of 4, 5 and 6 hours per day correspond to definition of good compliance
as mean daily CPAP use ≥ 4, ≥ 5 and ≥ 6 hours during follow-up, respectively, and of
poor compliance as mean daily CPAP use < 4, < 5 and < 6 hours during follow-up,
respectively. With cutoff 4 hours per day, the cohort included 208 patients, 94 CPAP
responders (45%) and 114 CPAP non-responders (55%). With cutoff 5 hours per day,
the resulting cohort included 125 patients, 89 CPAP responders (71%) and 36 CPAP
non-responders (29%). With cutoff 6 hours per day, the resulting cohort included 94
patients, 69 CPAP responders (73%) and 25 CPAP non-responders (27%). Univariate
logistic regression analysis was performed in order to determine the contribution of
each variable to residual excessive daytime sleepiness after CPAP therapy without
adjusting for other covariates. Multivariate logistic regression analysis was performed
in order to identify the variables that were independently associated with residual
excessive daytime sleepiness after CPAP therapy. All variables were determined at
baseline assessment. Depression was not included in the analyses because it offered a
near complete separation between CPAP responders and CPAP non-responders and
maximum likelihood estimation was not achieved. Among patients, the odds of having
residual excessive daytime sleepiness after CPAP therapy increased with the presence
of diabetes, heart disease, and higher Epworth sleepiness scale score and lower
respiratory disturbance index at baseline assessment.
OR: Odds ratio; CI: Confidence intervals.